The Xbox One OS, Windows 8.x OS and Windows Phone 8 OS already share a common Windows NT core. As we've heard before, Microsoft is working to deliver a single app store across its myriad Windows platforms. Company officials also are laboring to make the developer toolset for all three of these platforms more similar.

But Threshold will add another level of commonality across Microsoft's various Windows-based platforms, sources said. With the Threshold wave, Microsoft plans to support the same core set of "high value activities" across platforms. These high-value activities include expression/documents (Office, and the coming "Remix" digital storytelling app, I'd think); decision making/task completion (Bing, I'd assume); IT management (Intune and Workplace Join, perhaps?) and "serious fun."

The first bit seems like a no-brainer and should have been done already, but the second part seems like traditional Microsoft marketing nonsense. "High value activities"? Seriously? Could this be any more vague and meaningless?

Before Microsoft gets to Threshold, the company is on track to deliver an update to Windows 8.1 (known as Windows 8.1 Update 1) around the same time that it delivers Windows Phone "Blue" (Windows Phone 8.1). That's supposedly happening in the spring 2014/Q2 2014 timeframe, from what my sources have said.

With time frames like that it almost seems as if even Microsoft itself doesn't care.

I don't think Threshold or whatever is the holy grail end all be all grand unification that some have run with. Rather its another milestone on a multi release (and on a broader note, company wide) alignment.

Windows Phone 8 was the first step when they switched to NT and ported over a large portion of the Windows Runtime.

Windows Phone 8.1 will further this alignment in 2014. I expect to see more API convergence and common sense stopgap measures to bring platforms closer (single fee for WP and Win8 development was a start)

Threshold will come apparently after that and bring Xbox, Phone, Desktops, Laptops, and Tablets much closer together.

I think this is an admirable goal but it comes at a cost, and that cost is adding features some people want right now. Its hard to add new APIs to the Silverlight XAML stack when it will be moved over to the WinRT stack for example.